#! /bin/sh
###
### TrIPE interface initialization script
###   suitable for Linux; other operating systems probably want something
###   similar

###----- Licensing notica ---------------------------------------------------
###
### Redistribution, modification and use of this file is permitted without
### limitation.
###
### This file is distributed in the hope that it will be useful,
### but WITHOUT ANY WARRANTY; without even the implied warranty of
### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

set -e

## Import compile-time configuration.
: ${bindir=@bindir@}
: ${tripectl=$bindir/tripectl}
PATH=/usr/bin:/usr/sbin:/bin:/sbin:$bindir
export PATH TRIPEDIR

## Determine whether we have IPv6 support.
if [ -d /proc/sys/net/ipv6 ]; then have6=t; else have6=nil; fi

###--------------------------------------------------------------------------
### Error handling.

win=t
try () {
  if "$@"; then :; else
    rc=$?
    tripectl warn tripe-ifup command-failed rc=$rc "$*"
    win=nil
  fi
}

###--------------------------------------------------------------------------
### Collect arguments.

## Collect the simple arguments.
if [ $# -lt 3 ]; then
  echo >&2 "usage: $0 PEER IFNAME ADDR..."; exit 1
fi
peer=$1 ifname=$2 family=$3; shift 3

## Parse the address family.
case "$family" in
  INET) ipsz=20 ;;
  INET6) ipsz=40 ;;
  *) echo >&2 "$0: unknown address family $family"; exit 1 ;;
esac
case "$family,$#" in
  INET,1 | INET6,1) addr=$1 port=4070 ;;
  INET,2 | INET6,2) addr=$1 port=$2 ;;
  INET,* | INET6,*) echo >&2 "$0: bad $family address"; exit 1 ;;
  *) echo >&2 "$0: unknown address family $family"; exit 1 ;;
esac

###--------------------------------------------------------------------------
### Set the interface name.

case "${P_IFNAME+set}" in
  set)
    try ip link set "$ifname" name "$P_IFNAME"
    ifname=$P_IFNAME
    $tripectl setifname "$peer" "$ifname"
    ;;
esac

###--------------------------------------------------------------------------
### Configure the link.

## Split local addresses into v4 and v6 lists.
unset l4addr l6addr
for a in $P_LADDR; do
  case "$a" in
    *:*) l6addr=${l6addr+$l6addr }$a ;;
    *)   l4addr=${l4addr+$l4addr }$a ;;
  esac
done

## Determine the remote v4 and v6 addresses.  We only allow one remote
## address for each: others can be added as routes.
unset r4addr r6addr
for a in $P_RADDR; do
  case "$a" in
    *:*) r6addr=$a ;;
    *)   r4addr=$a ;;
  esac
done

## Configure the first v4 address as point-to-point; add the others as plain
## addresses.
haveaddr4=nil
set -- $l4addr
case $#,${r4addr+set} in
  [1-9]*,set)
    try ip addr add "$1" peer "$r4addr" dev "$ifname"
    haveaddr4=t
    shift
    ;;
esac
for a in "$@"; do
  try ip addr add "$a" dev "$ifname"
  haveaddr4=t
done

## IPv6 point-to-point links seem broken in Linux.  Attach the local and
## remote addresses by hand.
haveaddr6=nil
set -- $l6addr
case $have6,$# in
  t,[1-9]*)

    ## If we're configured to set IPv6 addresses then we should ensure that
    ## they're going to work, even if the default setting for new interfaces
    ## is to disable IPv6.
    try sysctl -q net.ipv6.conf."$ifname".disable_ipv6=0

    ## Now add the source and destination addresses.
    for a in "$@"; do
      try ip addr add "$a" dev "$ifname"
      haveaddr6=t
    done
    ;;
esac

###--------------------------------------------------------------------------
### Bring the interface up.

case $haveaddr4,$haveaddr6 in
  nil,nil)
    ;;
  *)
    case "${P_MTU+set}" in
      set)
	mtu=$P_MTU;;
      *)
	pathmtu=$(pathmtu "$addr")
	mtu=$(( $pathmtu - $ipsz - 9 - $A_BULK_OVERHEAD ))
	;;
    esac
    try ip link set dev "$ifname" up mtu "$mtu"
    ;;
esac

###--------------------------------------------------------------------------
### Set the peer IPv6 address if any.

## IPv6 point-to-point links seem broken in Linux.  Attach the local and
## remote addresses by hand.
set -- $l6addr
case $have6,$#,${r6addr+set} in
  t,[1-9]*,set)
    try ip route add $r6addr proto static dev "$ifname"
    ;;
esac

###--------------------------------------------------------------------------
### Set up routing.

## Split the routes into v4 and v6 lists.
unset route4 route6
for p in $P_NETS; do
  case "$p" in
    *:*) route6=${route6+$route6 }$p ;;
    *)   route4=${route4+$route4 }$p ;;
  esac
done

## Add the v4 routes.
set -- $route4
case $haveaddr4,$# in
  t,[1-9]*)
    for p in "$@"; do
      try ip route add $p proto static via "$r4addr"
    done
    ;;
esac

## Add the v6 routes.
set -- $route6
case $haveaddr6,$# in
  t,[1-9]*)
    for p in "$@"; do
      try ip route add $p proto static via "${r6addr%/*}"
    done
    ;;
esac

###--------------------------------------------------------------------------
### Maybe invoke a follow-on script.

case "${P_IFUPEXTRA+set}" in
  set)
    eval "$P_IFUPEXTRA"
    ;;
esac

###--------------------------------------------------------------------------
### Issue a notification that we've won.

case $win in
  t) $tripectl notify tripe-ifup configured "$peer" ;;
  nil) $tripectl notify tripe-ifup configured "$peer" failed ;;
esac

###----- That's all, folks --------------------------------------------------